<template>
  <div>
    <h2>随机点名</h2>
    <div class="box">
      <span>名字是：</span>
      <div class="qs">{{arr[index] || '这里显示姓名' }}</div>
    </div>
    <div class="btns">
      <button @click="on" class="start">开始</button>
      <button @click="off" class="end">结束</button>
    </div>
  </div>
</template>

<script>
export default {
  data() {
    return {
      arr: ['科幻','喜剧','动漫','冒险','科技','军事','娱乐','奇闻'],
      index: null,
      time1: null
    }
  },
  methods: {
    on(){
      if (this.time1) return
      this.time1 = setInterval(() => {
        this.index = parseInt(Math.random() * this.arr.length)
      } ,200)
    },
    off() {
      clearInterval(this.time1)
      this.time1 = null
    }
  }
};
</script>

<style scoped>
* {
  margin: 0;
  padding: 0;
}

h2 {
  text-align: center;
}

.box {
  width: 600px;
  margin: 50px auto;
  display: flex;
  font-size: 25px;
  line-height: 40px;
}

.qs {
  width: 450px;
  height: 40px;
  color: red;
}

.btns {
  text-align: center;
}

.btns button {
  width: 120px;
  height: 35px;
  margin: 0 50px;
}
</style>